Reference signal notification method and apparatus

ABSTRACT

Embodiments of the present invention provide a reference signal notification method, including: sending, by a network device, a reference signal notification message, where the reference signal notification message includes time resource information of a reference signal. According to the embodiments of the present invention, the reference signal notification message in the present invention is used to notify UE of a reference signal configuration, especially information about a CSI-RS, so that the network device can flexibly provide a reference signal, especially a CSI-RS, and the UE can more effectively receive the reference signal, especially the CSI-RS.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of International Application No.PCT/CN2018/085191, filed on Apr. 28, 2018, which claims priority toChinese Patent Application No. 201710314205.0, filed on May 5, 2017 andChinese Patent Application No. 201710335918.5, filed on May 12, 2017,all of which are hereby incorporated by reference in their entireties.

TECHNICAL FIELD

The present invention relates to the communications field, and inparticular, to a reference signal notification method and apparatus.

BACKGROUND

In a method for radio resource management (English full name: RadioResource Management, RRM for short) in an existing LTE system, ameasurement manner based on a downlink signal is used. To be specific, abase station sends a downlink reference signal, for example, a cellspecific reference signal (English full name: Cell Specific ReferenceSignal, CRS for short) at a fixed time-frequency location. UE measuresthe reference signal sent by the base station to obtain a measurementresult such as reference signal received power (English full name:Reference Signal Received Power, RSRP for short)/reference signalreceived quality (English full name: Reference Signal Received Quality,RSRQ for short), and reports the measurement result to the base station:and the base station determines a handover and movement of the UE (UEfor short).

A cell handover is an important process in a wireless network, and playsa very key role in ensuring wireless communication quality of the UE.For example, in an LTE wireless network, a base station in each cellsends a reference signal CRS. UE in a cell receives a reference signalsent by a base station in the current cell and a reference signal sentby a base station in a neighboring cell, and reports received referencesignal quality information such as RSRP to the base station in thecurrent cell. The base station in the current cell determines, based onthe information reported by the UE, whether the UE is to be handed overto another cell. For example, when RSRP, received by the UE, of thereference signal sent by the base station in the neighboring cell isgreater than RSRP, received by the UE, of the reference signal sent bythe base station in the current cell, the base station may sendsignaling to instruct the UE to be handed over to the neighboring cell,and make handover preparations and migrate data of the UE with the basestation in the neighboring cell. After receiving a handover instruction,the UE performs handover confirmation with the base station in theneighboring cell and initiates initial access. The UE may start toperform normal communication after successfully accessing the basestation in the neighboring cell. FIG. 1 is a schematic diagram of a cellhandover process. In the cell handover process, reference signalmeasurement is a relatively important step. However, only a fixedmeasurement manner based on a downlink reference signal is used in theexisting LTE system, and consequently there are excessively highoverheads on a network side. Therefore, there is a disadvantage that adetection manner for UE is not flexible enough.

SUMMARY

To resolve a technical problem, embodiments of the present inventionprovide a reference signal notification method and apparatus.

According to a first aspect, an embodiment of the present inventionprovides a reference signal notification method, including: sending, bya network device, a reference signal notification message, where thereference signal notification message includes time resource informationof a reference signal.

According to a second aspect, an embodiment of the present inventionprovides a reference signal notification method, including: receiving,by a terminal device, a reference signal notification message, where thereference signal notification message includes time resource informationof a reference signal.

According to a third aspect, an embodiment of the present inventionprovides a reference signal notification apparatus, including: atransceiver, where the transceiver is configured to send a referencesignal notification message, where the reference signal notificationmessage includes time resource information of a reference signal.

According to a fourth aspect, an embodiment of the present inventionprovides a reference signal notification apparatus, including: atransceiver, where the transceiver is configured to receive a referencesignal notification message, where the reference signal notificationmessage includes time resource information of a reference signal.

According to a fifth aspect, this application provides a computerreadable storage medium, including an instruction. When the instructionruns on a computer, the computer performs the reference signalnotification method according to the first aspect.

According to a sixth aspect, this application provides a computerreadable storage medium, including an instruction. When the instructionruns on a computer, the computer performs the reference signalnotification method according to the second aspect.

According to the embodiments of the present invention, the referencesignal notification message in the present invention is used to notifyUE of a reference signal configuration, especially information about aCSI-RS, so that the network device can flexibly provide a referencesignal, especially a CSI-RS, and the UE can more effectively receive thereference signal, especially the CSI-RS.

BRIEF DESCRIPTION OF DRAWINGS

To describe the technical solutions in the embodiments of the presentinvention or in the background more clearly, the following brieflydescribes the accompanying drawings required for describing theembodiments of the present invention or the background.

FIG. 1 shows an example of a handover process in LTE:

FIG. 2 is a schematic diagram of an example of a network architecturethat may be applied to an embodiment of the present invention:

FIG. 3 is a schematic diagram of an example of another networkarchitecture that may be applied to an embodiment of the presentinvention;

FIG. 4 is a schematic diagram of time-frequency resource mapping;

FIG. 5 is a schematic diagram of an example of a time-frequency resourceconfiguration of a synchronization signal block;

FIG. 6, FIG. 7, and FIG. 8 are schematic diagrams of time resourceinformation according to an embodiment of the present invention;

FIG. 9 is a schematic diagram of a reference signal notification methodaccording to an embodiment of the present invention:

FIG. 10 is a schematic diagram of another reference signal notificationmethod according to an embodiment of the present invention;

FIG. 11 is a schematic structural diagram of an apparatus according toan embodiment of the present invention; and

FIG. 12 is a schematic structural diagram of an apparatus according toan embodiment of the present invention.

DESCRIPTION OF EMBODIMENTS

The following describes the embodiments of the present invention withreference to the accompanying drawings in the embodiments of the presentinvention.

FIG. 2 is a schematic diagram of an example of a network architecturethat may be applied to an embodiment of the present invention. Theschematic diagram of the network architecture may be a networkarchitecture in an LTE communications system, may be an architecture ina universal mobile telecommunications system (Universal MobileTelecommunications System, UMTS) terrestrial radio access network (UMTSTerrestrial Radio Access Network, UTRAN) or an architecture in a globalsystem for mobile communications (Global System for MobileCommunications, GSM)/enhanced data rates for GSM evolution (EnhancedData Rates for GSM Evolution, EDGE) system radio access network (GSMEDGE Radio Access Network, GERAN), or may be an architecture in a 5thgeneration (5th Generation, 5G) mobile communications system. Theschematic diagram of the network architecture includes a mobilitymanagement entity (Mobility Management Entity, MME)/serving gateway(Serving GateWay, SGW), a base station, and user equipment (UserEquipment, UE). It should be noted that forms and quantities ofMMEs/SGWs, base stations, and UEs shown in FIG. 2 are used as an examplefor description, and constitute no limitation on the embodiments of thepresent invention.

The MME is a key control node in 3rd generation partnership project (3rdGeneration Partnership Project, 3GPP) LTE, is a core network element,and is mainly responsible for signaling processing, namely, controlplane functions, including functions such as access control, mobilitymanagement, attachment and detachment, a session management function,and gateway selection. The SGW is an important network element of thecore network element in 3GPP LTE, and is mainly responsible for a userplane function of forwarding user data, that is, routing and forwardinga data packet under control of the MME.

The base station is configured to communicate with the user equipment,and may be a base transceiver station (Base Transceiver Station, BTS) ina GSM system or a code division multiple access (Code Division MultipleAccess, CDMA) system, a NodeB (NodeB, NB) in a WCDMA system, an evolvedNodeB (evolved Node B, eNB) in an LTE system, or a gNB in a 5G system ora base station in a future communications system. The base station ismainly responsible for functions such as radio resource management on anair interface side, quality of service (Quality of Service, QoS)management, and data compression and encryption. For a core networkside, the base station is mainly responsible for forwarding controlplane signaling to the MME and forwarding user plane service data to theSGW.

The user equipment is a device that accesses a network side by using thebase station, and may include but is not limited to a cellular phone, acordless phone, a session initiation protocol (Session InitiationProtocol, SIP) phone, a wireless local loop (Wireless Local Loop. WLL)station, a personal digital assistant (Personal Digital Assistant. PDA),a handheld device or a computing device with a wireless communicationfunction, or another processing device connected to a wireless modem, avehicle-mounted device, a wearable device, or a terminal device in afuture 5G network.

An S1 interface shown in FIG. 2 is a standard interface between a basestation and a core network. The base station is connected to the MMEthrough an S1-MME interface, to control signaling transmission, and thebase station is connected to the SGW through an S1-U interface, toperform user data transmission. The S1-MME interface and the S1-Uinterface are collectively referred to as S1 interfaces.

An X2 interface shown in FIG. 2 is a standard interface between basestations, and is used to implement interworking between the basestations.

A Uu interface shown in FIG. 2 is a standard interface between userequipment and a base station, and the user equipment accesses an LTE/S5Gnetwork through the Uu interface.

Certainly, a wireless communications network (for example, an LTEnetwork) shown in FIG. 2 is cell-centered. Base stations in differentcells serve UE in the respective cells. When UE enters a neighboringcell from a current cell during movement, a cell handover occurs.However, a cell handover process is very complex, and signalingoverheads in the process are relatively high. Consequently, a relativelyhigh delay is caused, and negative impact may be imposed on userexperience of the UE to some extent.

FIG. 3 is a schematic diagram of an example of another networkarchitecture that may be applied to an embodiment of the presentinvention. The schematic diagram of the network architecture may be anetwork architectural diagram of new radio (New Radio, NR) in a nextgeneration wireless communications system. In the schematic diagram ofthe network architecture, one base station is divided into onecentralized unit (Centralized Unit, CU), and a plurality oftransmission/reception points (Transmission/Reception Point,TRP)/distributed units (Distributed Unit, DU). In other words, abandwidth-based unit (Bandwidth Based Unit, BBU) of the base station isreconfigured into function entities: the DU and the CU. It should benoted that forms and quantities of centralized units and TRPs/DUs shownin FIG. 3 are used as an example for description, and constitute nolimitation on the embodiments of the present invention. Although formsof centralized units corresponding to a base station 1 and a basestation 2 shown in FIG. 3 are different, functions of the base stationsare not affected. It may be understood that a centralized unit 1 and aTRP/DU that is within a range indicated by a dashed line are constituentelements of the base station 1, and a centralized unit 2 and a TRPDUthat is within a range indicated by a solid line are constituentelements of the base station 2. The base station 1 and the base station2 are base stations in an NR system.

The CU processes a function of an upper radio protocol stack layer, forexample, a radio resource control (Radio Resource Control, RRC) layer ora packet data convergence protocol (Packet Data Convergence Protocol.PDCP) layer, and even can support transferring some core networkfunctions down to an access network. A term is referred to as an edgecomputing network. The edge computing network can meet a higher networkdelay requirement of emerging services such as a video, online shopping,and virtual/augmented reality on a future communications network.

The DU mainly processes a physical layer function, and a layer 2function with a relatively high real-time requirement. In view oftransmission resources of a radio remote unit (Radio Remote Unit, RRU)and the DU, some physical layer functions of the DU may be transferredup to the RRU. As the RRU becomes smaller, the DU may be even combinedwith the RRU.

CUs may be deployed in a centralized manner. DUs are deployed based onan actual network environment. In a core urban area or an area withrelatively high traffic intensity, a relatively short distance betweenstations, and limited equipment room resources, for example, a campus ora large-scale performance venue, DUs may also be deployed in acentralized manner. In an area with relatively low traffic intensity anda relatively long distance between stations, for example, a suburb or amountainous area. DUs may be deployed in a distributed manner.

An S1-C interface used as an example in FIG. 3 may be a standardinterface between a base station and a core network, and specificdevices connected through the S1-C interface are not shown in FIG. 3.

In the embodiments of the present invention, a CSI-RS may be used as ameasurement manner for UE in a downlink connected mode.

The following describes application of the CSI-RS in LTE.

A channel state information-reference signal CSI-RS is an importantreference signal in an LTE network, and is mainly used by UE to obtainradio channel state information CSI. In the LTE network, the CSI-RS maybe transmitted through a maximum of 32 antenna ports (antenna port), andcorresponding antenna port numbers are p=15, 16, . . . , 42. As for theantenna port, a spatial dimension in LTE is measured in terms of “layer(layer)”, and is implemented by using a multiple-antenna transmissiontechnology and a multiple-antenna reception technology. Each layercorresponds to one effective data flow, and is mapped to a logicalantenna port. Each antenna port corresponds to one time-frequencyresource grid, and corresponds to one reference signal, so that areceive end performs channel estimation, coherent demodulation, and thelike.

A sequence of the CSI-RS in frequency domain is defined as follows:

${{r_{i,n_{s}}(m)} = {{\frac{1}{\sqrt{2}}\left( {1 - {2 \cdot {c\left( {2\; m} \right)}}} \right)} + {j\; \frac{1}{\sqrt{2}}\left( {1 - {2 \cdot {c\left( {{2\; m} + 1} \right)}}} \right)}}},{m = 0},1,\ldots \mspace{14mu},{N_{RB}^{\max,{DL}} - 1},$

where

n_(s) is a sequence number of a slot (slot) in a radio frame (radioframe), l is a sequence number of an orthogonal frequency divisionmultiplexing (Orthogonal Frequency Division Multiplexing, OFDM) symbolin a slot, c(i) is a pseudo random sequence, and each OFDM symbol isinitialized by using c_(init). c_(init) is defined as follows:

c _(init)=2¹⁰·(7·(n′ _(s)+1)+l+1)·(2·N _(ID) ^(CSI)+1)+2·N _(ID) ^(CSI)+N _(CP).

A relatively key parameter is N_(ID) ^(CSI), and N_(ID) ^(CSI) may be acell identity or a virtual cell identity, and ranges from 0 to 503. Abase station in LTE periodically sends a CSI-RS signal. A period may be5 milliseconds, 10 milliseconds, 20 milliseconds, 40 milliseconds, or 80milliseconds. In addition, CSI-RSs sent on different antenna ports mayoccupy different time-frequency resources. FIG. 4 is a schematic diagramof a mapping relationship of a CSI-RS in a physical resource block pair,where R₁₅ and R₁₇ respectively represent a CSI-RS signal on an antennaport 15 and a CSI-RS signal on an antenna port 17.

The foregoing description about the CSI-RS in LTE may be used as asupplement to the embodiments of the present invention. In theembodiments of the present invention, application of a CSI-RS furtherchanges compared with that in LTE. In the embodiments of the presentinvention, the CSI-RS may be used as a measurement manner for UE in adownlink connected mode, but this cannot be implemented in an LTEcommunications system. To use a CSI-RS as a measurement manner for UE ina downlink connected mode, a network device needs to notify the userequipment of a CSI-RS configuration, especially time resourceinformation, so that the user equipment performs CSI-RS measurement andreporting. The embodiments of the present invention provide a referencesignal notification method and apparatus, and in particular, a CSI-RSnotification method and apparatus, to effectively improve mobilitymeasurement efficiency.

The method and apparatus provided in the embodiments of the presentinvention may be applied to the schematic diagram of the networkarchitecture shown in FIG. 2 or FIG. 3. The network device in theembodiments of the present invention may be the base station shown inFIG. 2, may be the TRP/DU shown in FIG. 3, or may be a combination of aTRP/DU and a CU. The user equipment in the embodiments of the presentinvention may include but is not limited to a cellular phone, a cordlessphone, a handheld device or a computing device with a wirelesscommunication function, or another processing device connected to awireless modem, a vehicle-mounted device, a wearable device, or aterminal device in a future 5G network. In addition, although aplurality of network elements are included in the embodiments of thepresent invention, it does not indicate that all the network elementsshould be included in the protection solutions of this application.

The following briefly describes a synchronization signal block(Synchronization Signal block, SS block) and describes an SS blocktiming index. FIG. 5 is a schematic diagram of an example of atime-frequency resource configuration of an SS block. It can be learnedfrom the example in FIG. 5 that the SS block includes a PSS, an SSS, anda PBCH. The PSS and the SSS each may occupy one OFDM symbol, and thePBCH may occupy two or more OFDM symbols. A plurality of SS blocks mayconstitute one subframe. It may be understood that one SS block maycorrespond to one beam of a network device, and measuring a beam isactually measuring a measurement signal in the SS block corresponding tothe beam. It may also be understood that a plurality of SS blockscorrespond to one beam of a network device, and measuring a beam isactually measuring a measurement signal in the plurality of SS blockscorresponding to the beam.

FIG. 5 is a schematic diagram of an example of resource structures of asynchronization channel and a broadcast channel. A synchronizationsignal and a broadcast signal constitute one SS block (English: SSblock), one or more SS blocks constitute one SS burst (English: SSburst), and one or more SS bursts constitute one SS burst set (English:SS burst set). In a transmission period, for example, in a period of anSS burst set, there may be a plurality of SS blocks, and a terminaldevice cannot determine a location of a detected SS block in theplurality of SS blocks only through detection of a synchronizationsignal. Therefore, each SS block has a time index (English: time index).The time index indicates a location of the SS block in a plurality of SSblocks, or may be understood as indicating a ranking of the SS block ina plurality of SS blocks. The time index of each SS block may be carriedin a PBCH of the SS block. The UE obtains information about the SS blocktime index in the PBCH, to obtain time synchronization information ofthe cell. The time synchronization information includes informationabout frame synchronization/slot synchronization/symbol synchronization.In this case, time synchronization cannot be implemented and a radioframe structure cannot be determined.

The following describes in detail the reference signal notificationmethod provided in the embodiments of the present invention.

FIG. 9 is a schematic flowchart of a reference signal notificationmethod according to an embodiment of the present invention. The methodis described from a perspective of interaction between a network deviceand user equipment (UE for short). However, in the protection scope ofthis embodiment of the present invention, there is no limitation thatboth of the network device and the UE are required, and only the networkdevice or only the UE may be included. The method includes but is notlimited to the following processing.

S101. The UE measures an SS block of a current cell and/or an SS blockof a neighboring cell, where this process is optional.

S103. The UE sends information about the SS block of the current celland/or the neighboring cell, where this process is optional. Optionally,the information is sent to a network device. Further optionally, theinformation is sent to a network device in the current cell. For ease ofdescription, the network device is represented by a gNB, but is notlimited to the gNB in implementation. Optionally, the gNB receives theinformation that is about the SS block of the current cell and/or theneighboring cell and that is fed back by the UE.

S105. A gNB sends a reference signal notification message, andoptionally, a gNB in the current cell sends a reference signalnotification message. Optionally, the gNB sends the notification messageto the UE. Further optionally, the UE receives the reference signalnotification message.

A cell to which a serving base station belongs may be referred to as thecurrent cell. The gNB may be a source base station in a handoverprocess. The gNB has one or more neighboring cells. The UE may be handedover from the source base station to a target base station. The targetbase station may be a base station in the one or more neighboring cellsof the source base station. Each term in this embodiment of thisapplication is merely an example. A person skilled in the art may knowthat another name may be used.

A reference signal may be a CSI-RS, and further may be a CSI-RS of theneighboring cell, may be a CSI-RS of the neighboring cell, may be aCSI-RS corresponding to a cell ID of the neighboring cell, or the like.

The notification message includes time resource information of areference signal. The time resource information may be but not limitedto the following information:

1. The CSI-RS may be a CSI-RS of the neighboring cell, and the timeresource information may be time resource information of the CSI-RS.Further, the time resource information may be subframe configurationinformation of the CSI-RS, and further the time resource information maybe subframe configuration information of the CSI-RS of the neighboringcell. The subframe configuration information may be subframeconfiguration index information. Different subframe configuration indexinformation indicates different subframe configurations. The followingprovides an example of the subframe configuration index information in atable methods. In this embodiment of this application, the table form isused as an example, and this is not limited to the table form in actualimplementation. Another form such as a formula may be alternativelyused, and details are not described below. For ease of description, anexample of the subframe configuration information is denoted asCSI-RS-subframeconfig. For example, a configuration manner in Table 1 isas follows:

TABLE 1 CSI-RS CSI-RS- periodicity CSI-RS subframe subframeconfigT_csi-rs offset delta_csi-rs I_csi-rs (subframes) (subframes) 0-4 5I_csi-rs  5-14 10 I csi-rs − 5  15-34 20 I csi-rs − 15 35-74 40 I_csi-rs− 35  75-154 80 I_csi-rs − 75

The example of CSI-RS-subframeconfig corresponds to subframeconfiguration indexes with values 0 to 154, as shown in the firstcolumn. Each value corresponds to one CSI-RS period value, as shown inthe second column, and corresponds to an offset of the CSI-RS in theperiod, as shown in the third column. A subframe of the CSI-RS needs tomeet the following condition: (10n_(f)+└n_(s)/2┘−Δ_(CSI-RS))modT_(CSI-RSS)=0, where n_(f) is a system frame number, the system framenumber may be obtained by using system information, and the system framenumber may range from 0 to 1023, and n_(s) is a number of a slot in asystem frame, and the slot number may be denoted as a slot number, andmay range from 0 to 19.

The subframe configuration information of the CSI-RS may be indicatedbased on a cell ID. Optionally, the subframe configuration indexinformation of the CSI-RS may be indicated based on a cell ID. In thisway, subframes of CSI-RSs of different cells are staggered in time. Foreach cell, a cell ID mod 504 operation is performed based on the cell IDand 504, and an obtained result corresponds to a CSI-RS-subframeconfigvalue, and therefore a subframe, for sending a CSI-RS, corresponding tothe cell is obtained. For all UEs in the cell, subframe configurationsof the CSI-RS may be the same. An example is shown in Table 2. In thiscase, the time resource information of the CSI-RS of the neighboringcell, for example, the subframe configuration information of CSI of theneighboring cell can be indicated provided that the gNB adds informationabout a cell ID of the neighboring cell to the notification message.This indication manner is an implicit indication manner in whichsignaling overheads can be reduced.

TABLE 2 CSI-RS CSI-RS- periodicity CSI-RS subframe Cell IDsubframeconfig T_csi-rs offset delta_csi-rs mod 504 I_csi-rs (subframes)(subframes) 0-4 0-4 5 I_csi-rs  5-14  5-14 10 I_csi-rs − 5  15-34 15-3420 I_csi-rs − 15 35-74 35-74 40 I_csi-rs − 35  75-154  75-154 80I_csi-rs − 75

2. The CSI-RS may be a CSI-RS of the neighboring cell of the gNB, andthe time resource information may be a time offset. For example, thetime offset may have the following two forms:

(a) The time resource information may be a time offset corresponding toa subframe of the CSI-RS. Further, the time resource information may bea time offset corresponding to a subframe of the CSI-RS of theneighboring cell, and the time offset may be an offset based on an SSblock. The SS block may be an SS block of the neighboring cell, or maybe an SS block of the current cell. The SS block may be one or more SSblocks fed back by the UE. Further. The SS block may be an optimal SSblock in one or more SS blocks fed back by the UE. For example, the timeoffset may be represented as a delta shown in FIG. 6 or FIG. 8. Each SSblock corresponds to one CSI-RS after a time offset of the SS block.Therefore, after reading an SS block, the UE obtains a time location ofa CSI-RS with reference to the time offset delta, and the UE performsCSI-RS measurement at the location of the CSI-RS. In FIG. 8. B2 may bean SS block fed back by the UE. FIG. 6 is merely an example. The threeSS blocks may be SS blocks fed back by the UE, or may represent any SSblock. Although there are three consecutive SS blocks in FIG. 6, thisconstitutes no limitation. There may be an SS block in another form, orthere may be only one SS block.

(b) The time resource information may be a time boundary of the currentcell. A granularity of the time boundary may be a frame boundary, asubframe boundary, a slot boundary, or a symbol boundary, or may be aboundary of an SS block of the current cell. The granularity may be theforegoing various granularities. For example, The boundary of the SSblock may be the first symbol, the last symbol, the first subframe, thelast subframe, or the like of the SS block. The time offset may be at asymbol level, for example, 10 symbols, or may be at a slot level or asubframe level, for example, two subframes.

3. The time resource information may be measurement window information.The UE may perform CSI-RS measurement at a possible CSI-RS location in acorresponding measurement window. For example, as shown in FIG. 7, afterreading an SS block, the UE obtains a possible time location t1 of theCSI-RS based on information that the SS block is the first SS block andwith reference to a time offset delta, and obtains a possible timelocation tn of the CSI-RS based on an n^(th) SS block after the SS blockand with reference to the time offset delta. In this case, the UEperforms CSI-RS measurement in a period from t1 to tn, where n may be apositive integer greater than 1.

Optionally, the notification message includes beam information of thereference signal. If no beam information of the reference signal iscarried in the notification message, the CSI-RS of the neighboring cellmay be sent in all beam sending directions of a downlink CSI-RS, inother words, a manner of performing scanning in all possible beamdirections may be used. If the beam information of the reference signalis carried in the notification message, the CSI-RS of the neighboringcell may be sent in a beam direction indicated in the notified beaminformation. The beam information may be information about an SS block,and further may be information about an SS block of the neighboringcell, for example, a time index of the SS block of the neighboring cell.The beam information may be information about one or more SS blocks fedback by the UE, may be information about all or some of one or more SSblocks fed back by the UE, or may be understood as information about oneor more SS blocks in one or more SS blocks fed back by the UE.

A process in which the UE feeds back information about one or more SSblocks of the neighboring cell may be as follows:

1. The UE measures an SS block of the neighboring cell to obtain timesynchronization information of the neighboring cell. The timesynchronization information of the neighboring cell may include symbolsynchronization, frame synchronization, slot synchronization, or thelike.

2. The UE feeds back, to the gNB in the current cell, the informationabout the one or more SS blocks of the neighboring cell that aremeasured by the UE. The information about the SS block may include atime index of the SS block, and optionally, further includes SS blockRSRP information corresponding to the SS block. The information aboutthe one or more SS blocks that is fed back may be but not limited toinformation about all SS blocks measured by the UE, information aboutsome of SS blocks measured by the UE, or information about one or moreoptimal SS blocks obtained through measurement.

The gNB receives the information about the one or more SS blocks that isfed back by the UE, and obtains beam information of the CSI-RS of theneighboring cell based on the information about the one or more SSblocks that is fed back by the UE. The information about the SS blockthat is fed back by the UE is usually about an SS block with betterreceived signal quality. Therefore, for a beam direction in which theCSI-RS is sent, refer to a beam direction of the SS block that is fedback.

The beam information of the reference signal may be information aboutone or more SS blocks in one or more SS blocks fed back by the UE.

In an implementation process, the beam information of the referencesignal may be notified in a plurality of implementations.

In an example of Table 3, in addition to subframe configurationinformation of the CSI-RS in the first column, the reference messagenotification message further includes SS block information and an SSblock time index. For example, Ti_1 . . . and Ti_10 are SS block timeindexes with a value range of [0, 63], and there may be differentconfigurations. Certainly, there may be a correspondence such as aone-to-many correspondence, a many-to-one correspondence, or amany-to-many correspondence between subframe configuration informationof a CSI-RS and SS block information, and the correspondence may berepresented by using a table, a formula, a function, or the like.

TABLE 3 CSI-RS CSI-RS- periodicity CSI-RS subframe Associatedsubframeconfig T_csi-rs offset delta_csi-rs SS block I_csi-rs(subframes) (subframes) time index 0-4 5 I_csi-rs Ti_1 and Ti_2  5-14 10I_csi-rs − 5  Ti_3 and Ti_4 15-34 20 I_csi-rs − 15 Ti_5 and Ti_6 35-7440 I_csi-rs − 35 Ti_7 and Ti_8  75-154 80 I_csi-rs − 75 Ti_9 and Ti_10

Optionally, the reference signal notification message may optionallyinclude one or more pieces of the following information, and for the gNBor the UE in the current cell, the information is all about theneighboring cell:

A. A cell identity, for example, a cell ID. For details, refer to thedescription of Table 2. A cell corresponding to the CSI-RS may beidentified by carrying the cell ID.

B. Period information corresponding to a subframe of the CSI-RS. If thereference information notification message carries the periodinformation, it indicates that the CSI-RS is configured periodically. Ifthe reference information notification message does not carry the periodinformation, it indicates that the CSI-RS is aperiodically configured,and each SS block needs to be read first, and then a correspondingCSI-RS is obtained.

C. Bandwidth information of the CSI-RS. The bandwidth may be a systembandwidth, or may be a partial bandwidth of a system bandwidth. Thebandwidth information is carried, so that measurement can be performedmore flexibly. The system bandwidth can provide higher measurementprecision, and the partial bandwidth may adapt to UEs with differentcapabilities. For example, some UEs can perform measurement only on thepartial bandwidth or it is more suitable for some UEs to performmeasurement on the partial bandwidth.

D. Antenna port information of the CSI-RS. The antenna port informationof the CSI-RS may be delivered in RRC signaling. The antenna port maybe, for example, one or more of values such as {1, 2, 4, 8, 16}.Certainly, a port set is not limited to {1, 2, 4, 8, 16}, and may beanother combination. Different quantities of antenna ports areindicated, so that the UE can measure different quantities ofneighboring cells, thereby implementing higher measurement flexibility.

The antenna port information of the CSI-RS may be further associatedwith the foregoing beam information, and an example is shown in Table 4:

TABLE 4 SS block time index 1 CSI-RS ports 15 and 16; CSI-RS ports 17and 18; CSI-RS ports 19 and 20; SS block time index 2 CSI-RS ports 21and 22 SS block time index 3 CSI-RS ports 23 and 24; CSI-RS ports 25 and26;

A beam sending direction of an SS block corresponding to the SS blocktime index 1 corresponds to beam directions of CSI-RSs sent throughports 15 and 16, ports 17 and 18, and ports 19 and 20. For example, asshown in FIG. 8, a beam B2 corresponding to an SSB 2 may correspond tothree beams B21 to B23 of a CSI-RS. A beam sending direction of an SSblock corresponding to the SS block time index 3 corresponds to beamdirections of CSI-RSs sent through ports 23 and 24, and ports 25 and 26.

E. Numerology information of the CSI-RS. The numerology may beconsistent with a numerology of a synchronization signal, or may beconsistent with a numerology of data. In terms of form, a numerologyindex may be notified. For example, the numerology may be differentvalues of subcarrier spacings {15, 30, 60, 120, 240 kHz}. In this case,the numerology index may be represented by three bits, and differentvalues of the numerology index represent different numerologies. ACSI-RS can be more flexible by using a numerology carrying the CSI-RS.For example, a subcarrier spacing of the CSI-RS is configured to bedifferent from a subcarrier spacing of data. This helps the UE toconfigure more CSI-RS resources in a slot, and helps a plurality of UEsto use a same subcarrier spacing that is different from a subcarrierspacing of a data part, so that measurement is more comparable.

F. Time-frequency resource mapping relationship information of theCSI-RS, namely, a time-frequency resource location of an RE.

Optionally, the gNB may send the reference signal notification messageby using RRC signaling or a broadcast message. The RRC signaling may bespecific to a user.

Optionally, the gNB may send the reference signal notification messagein, without limitation to, the following one or more conditions:

-   -   i. The gNB detects that the UE is at a boundary of the current        cell.    -   ii. The gNB detects that SS block RSRP, measured by the UE, of        the current cell is relatively low, for example, is lower than a        threshold.    -   iii. The gNB detects that SS block RSRP, fed back by the UE, of        the neighboring cell is relatively high, for example, exceeds a        threshold.

S107. The UE receives a reference signal based on the reference signalnotification message. For example, the UE may determine, based on an SSblock time index, a direction for receiving a CSI-RS. The UE reads an SSblock, obtains, based on a timing offset, configuration informationincluding CSI-RS timing, determines a location of the CSI-RS, andperforms CSI-RS measurement and feedback. Alternatively, it may beunderstood as that the UE reads a PBCH broadcast message of theneighboring cell, to obtain configuration information of the CSI-RS ofthe cell, and receives a reference signal, namely, the CSI-RS, based onthe configuration information of the CSI-RS.

FIG. 10 is a schematic flowchart of another reference signalnotification method according to an embodiment of the present invention.A gNB in a neighboring cell sends a reference signal notificationmessage to UE.

For S201 and S203, refer to the description in the embodiment in FIG. 9.

In this embodiment, in S205, a gNB sends a reference signal notificationmessage. Optionally, the gNB in the neighboring cell provides anotification about the reference signal notification message. Forinformation included in the reference signal notification message, referto the description in the embodiment in FIG. 9. A difference between theinformation described in FIG. 9 and that described in FIG. 10 is that inFIG. 9, the gNB in the current cell provides a notification to the UE,and therefore for the gNB in the current cell or the UE, a large amountof information is information about the neighboring cell, but in thisembodiment, the gNB in the neighboring cell provides a notification tothe UE, and therefore for the gNB in the neighboring cell, a largeamount of information may be information about the current cell, andcertainly, may be information about the neighboring cell for the UE. Forexample, if no cell handover is performed, and a serving cell remains asource cell other than a target cell, the information may be informationabout the neighboring cell.

For S207, refer to the description in the embodiment in FIG. 9.

It can be learned from the foregoing description of the method in theembodiments of the present invention that according to the method orapparatus in the embodiments of the present invention, a referencesignal configuration message, especially information about a CSI-RS, isnotified to the UE, so that the network device can flexibly provide areference signal, especially a CSI-RS, and the UE can more effectivelyreceive the reference signal, especially the CSI-RS. Therefore,overheads of the reference signal, especially overheads of the CSI-RScan be effectively reduced.

The foregoing describes the method embodiments of the present inventionin detail. The following describes an apparatus in an embodiment of thepresent invention.

FIG. 11 is a schematic block diagram of a reference signal notificationapparatus 1100 according to an embodiment of the present invention. Theapparatus 1100 may be a network device.

It should be understood that the apparatus 1100 may correspond to thenetwork device in the method embodiments, and may have any function ofthe network device in the method.

As shown in FIG. 11, the apparatus 1100 includes a transceiver 1120, andoptionally, further includes a processor 1110.

The transceiver is configured to send a reference signal notificationmessage, where the reference signal notification message includes timeresource information of a reference signal.

Optionally, the reference signal is a CSI-RS, and the time resourceinformation is at least one of subframe configuration information, atime offset, and measurement window information of the CSI-RS.

Optionally, the reference signal is the CSI-RS, and the reference signalnotification message further includes one or more pieces of thefollowing information:

beam information of the CSI-RS, a cell identity, period informationcorresponding to a subframe of the CSI-RS, bandwidth information of theCSI-RS, antenna port information of the CSI-RS, numerology informationof the CSI-RS, and time-frequency resource mapping relationshipinformation of the CSI-RS.

Optionally, the time resource information and/or the beam informationare/is information about one or more SS blocks fed back by a terminaldevice.

Optionally, the transceiver may be configured to receive informationthat is about an SS block of a current cell and/or a neighboring celland that is fed back by the UE.

Optionally, the processor may be configured to: determine contentincluded in the reference signal notification message, and/or generatethe reference signal notification message. Further, the processordetermines, based on the information that is about the SS block of thecurrent cell and/or the neighboring cell and that is fed back by the UE,the content included in the reference signal notification message,and/or generates the reference signal notification message. For aspecific determining method and generation method, refer to theforegoing method embodiments.

FIG. 12 is a schematic block diagram of a reference signal notificationapparatus 1200 according to another embodiment of the present invention.The apparatus 1200 may be a terminal device.

It should be understood that the apparatus 1200 may correspond to theterminal device in the method embodiments, and may have any function ofthe terminal device in the method.

As shown in FIG. 12, the apparatus 1200 includes a transceiver 1220, andoptionally, further includes a processor 1210.

In an embodiment, the transceiver 1220 is configured to receive areference signal, where the reference signal is sent on a specifictime-frequency resource, and the specific time-frequency resource is ona symbol corresponding to a synchronization signal block. Optionally,the reference signal is a CSI-RS, and a time resource information is atleast one of subframe configuration information, a time offset, andmeasurement window information of the CSI-RS.

Optionally, the reference signal is the CSI-RS, and a reference signalnotification message further includes one or more pieces of thefollowing information:

beam information of the CSI-RS, a cell identity, period informationcorresponding to a subframe of the CSI-RS, bandwidth information of theCSI-RS, antenna port information of the CSI-RS, numerology informationof the CSI-RS, and time-frequency resource mapping relationshipinformation of the CSI-RS.

Optionally, the time resource information and/or the beam informationare/is information about one or more SS blocks fed back by the terminaldevice.

Optionally, the processor 1210 is further configured to measure an SSblock of a current cell and/or an SS block of a neighboring cell.

Optionally, the transceiver 1220 is further configured to sendinformation about the SS block of the current cell and/or theneighboring cell.

Optionally, the transceiver 1220 is configured to receive the referencesignal based on the reference signal notification message.

For specific functions of the processor 1210 and the transceiver 1220,refer to the foregoing method embodiments. Details are not describedagain.

It should be understood that the processor 1110 or the processor 1210 inthe embodiments of the present invention may be implemented by using aprocessing unit or a chip. Optionally, in an implementation process, theprocessing unit may include a plurality of units, for example, a mappingunit, and/or a signal generation unit, and/or a channel estimation unit.

It should be understood that the transceiver 1120 or the transceiver1220 in the embodiments of the present invention may be implemented byusing a transceiver unit or a chip. Optionally, the transceiver 1120 orthe transceiver 1220 may include a transmitter or a receiver, or includea transmission unit or a receiving unit.

It should be understood that the processor 1110 and the transceiver 1120in the embodiments of the present invention may be implemented by usinga chip, and the processor 1210 and the transceiver 1220 may beimplemented by using a chip.

Optionally, the network device or the terminal device may furtherinclude a memory. The memory may store program code, and the processorinvokes the program code stored in the memory, to implement acorresponding function of the network device or the terminal device.Optionally, the processor and the memory may be implemented by using achip.

An embodiment of the present invention further provides a processingapparatus, including a processor and an interface.

The processor is configured to perform the method in the embodiments ofthe present invention.

The processing apparatus may be a chip. The processor may be implementedby using hardware or software. When the processor is implemented byusing hardware, the processor may be a logic circuit, an integratedcircuit, or the like. When the processor is implemented by usingsoftware, the processor may be a general purpose processor, and isimplemented by reading software code stored in a memory. The memory maybe integrated into the processor, or may be located outside theprocessor and exist independently.

For example, the processing apparatus may be a field programmable gatearray (Field Programmable Gate Array, FPGA), an application-specificintegrated circuit (Application Specific Integrated Circuit, ASIC), asystem on chip (System on Chip, SoC), a central processor unit (CentralProcessor Unit, CPU), a network processor (Network Processor, NP), adigital signal processing circuit (Digital Signal Processor, DSP), amicro controller unit (Micro Controller Unit, MCU), a programmable logicdevice (Programmable Logic Device, PLD), or another integrated chip.

An embodiment of the present invention further provides a communicationssystem, including the network device in the foregoing network deviceembodiment and the terminal device in the foregoing terminal deviceembodiment.

To describe the solutions more clearly, description is added based on anapplication No. 201710314205.0 entitled “REFERENCE SIGNAL NOTIFICATIONMETHOD AND APPARATUS”, without increasing or changing the solutions:

In the description in the foregoing embodiment, the description that“FIG. 9 is a schematic flowchart of a reference signal notificationmethod according to an embodiment of the present invention. The methodis described from a perspective of interaction between a network deviceand user equipment (UE for short). However, in the protection scope ofthis embodiment of the present invention, there is no limitation thatboth of the network device and the UE are required, and only the networkdevice or only the UE may be included. The method includes but is notlimited to the following processing” may be described more clearly asfollows: “FIG. 9 is a schematic flowchart of a reference signalnotification method according to an embodiment of the present invention.The method is described from a perspective of interaction between anetwork device and user equipment or a terminal device (where the userequipment or the terminal device may be referred to as UE). However, inthe protection scope of this embodiment of the present invention, thereis no limitation that both of the network device and the UE arerequired, and only the network device or only the UE may be included.The method includes but is not limited to the following processing”.

In the description in the foregoing embodiment, a clerical error occursin the description that “In an embodiment, the transceiver 1220 isconfigured to receive a reference signal, where the reference signal issent on a specific time-frequency resource, and the specifictime-frequency resource is on a symbol corresponding to asynchronization signal block”. Based on other parts of this application,for clearer description, this sentence may be described as follows: “Inan embodiment, the transceiver 1220 is configured to receive a referencesignal notification message, where the reference signal notificationmessage includes time resource information of a reference signal”.

Based on the foregoing embodiments, added description is provided asfollows: Three s of examples of the time resource information areprovided in the foregoing embodiments. Herein, the time resourceinformation is further described.

For the first type of time resource information:

Added description is provided as follows:

In the foregoing embodiment, there is the description that “The timeresource information may be time resource information of the CSI-RS.Further, the time resource information may be subframe configurationinformation of the CSI-RS, and further the time resource information maybe subframe configuration information of the CSI-RS of the neighboringcell”. Further, the time resource information may be based on theneighboring cell or may be based on the current cell. Table 1 and Table2 are still used as examples, and this is not limited to a table form.The subframe configuration information in Table 1 and Table 2 may bebased on time of the neighboring cell or may be based on time of thecurrent cell.

Therefore, the reference signal notification message may further includereference information used to indicate a reference of the time resourceinformation. For example, the reference information is used to indicatewhether the time resource information is based on the current cell orthe neighboring cell. For example, one bit is used. When a value is 0,it indicates that the time resource information is based on the currentcell: or when a value is 1, it indicates that the time resourceinformation is based on the neighboring cell.

For the second type of time resource information:

(a) Added description is provided as follows:

The reference signal notification message may further include referenceinformation used to indicate a reference of the time resourceinformation. For example, the reference information is used to indicatewhether the time resource information is based on the current cell orthe neighboring cell. For example, one bit is used. When a value is 0,it indicates that the time resource information is based on the currentcell: or when a value is 1, it indicates that the time resourceinformation is based on the neighboring cell. In the manner (a),alternatively, the reference information may be specifically understoodas whether an SS block indicated in the time resource information is anSS block of the current cell or an SS block of the neighboring cell. Forexample, as shown in the examples in FIG. 6 and FIG. 8, the timeresource information may include SS block information (may be an SSblock time index) and/or an offset delta. Further, it can be learned,with reference to the reference information, whether the SS block in thetime resource information is an SS block of the current cell or an SSblock of the neighboring cell. In FIG. 6 and FIG. 8, the first symbol ofthe SS block is used as a start location of the delta. However, a personskilled in the art knows that in implementation, the start location maybe not limited to the first symbol, and the last symbol or anyintermediate symbol may be used as the start location.

(b) Added description is provided as follows:

For the original paragraph:

“(b) The time resource information may be a time boundary of the currentcell. A granularity of the time boundary may be a frame boundary, asubframe boundary, a slot boundary, or a symbol boundary, or may be aboundary of an SS block of the current cell. The granularity may be theforegoing various granularities. For example, The boundary of the SSblock may be the first symbol, the last symbol, the first subframe, thelast subframe, or the like of the SS block. The time offset may be at asymbol level, for example, 10 symbols, or may be at a slot level or asubframe level, for example, two subframes”.

The original paragraph may be understood and described as follows:

(b) The time resource information may be a time offset corresponding toa subframe of the CSI-RS. The time resource information may be based ona time boundary of the current cell or based on a time boundary of theneighboring cell. A granularity of the time boundary may be a frameboundary, a subframe boundary, a slot boundary, or a symbol boundary.The granularity may be the foregoing various granularities. The timeoffset may be at a symbol level, for example, 10 symbols, or may be at aslot level or a subframe level, for example, two subframes. Thereference signal notification message may further include referenceinformation used to indicate a reference of the time resourceinformation. For example, the reference information is used to indicatewhether the time resource information is based on the current cell orthe neighboring cell. For example, one bit is used. When a value is 0,it indicates that the time resource information is based on the currentcell; or when a value is 1, it indicates that the time resourceinformation is based on the neighboring cell. In the manner (b),alternatively, the reference information may be specifically understoodas whether a frame, a subframe, a slot, or a symbol indicated in thetime resource information is a frame, a subframe, a slot, or a symbol ofthe current cell, or a frame, a subframe, a slot, or a symbol of theneighboring cell. For example, the time resource information may includean offset (which may be represented as a delta) and information about aframe, a subframe, a slot, or a symbol. Further, it can be learned,based on the reference information, whether the frame, the subframe, theslot, or the symbol indicated in the time resource information is aframe, a subframe, a slot, or a symbol of the current cell, or a frame,a subframe, a slot, or a symbol of the neighboring cell.

For the third type of time resource information:

Added description is provided as follows:

The reference signal notification message may further include referenceinformation used to indicate a reference of the time resourceinformation. For example, the reference information is used to indicatewhether the time resource information is based on the current cell orthe neighboring cell. For example, one bit is used. When a value is 0,it indicates that the time resource information is based on the currentcell: or when a value is 1, it indicates that the time resourceinformation is based on the neighboring cell. In the measurement windowmanner, as shown in the example in FIG. 7, the time resource informationmay be an offset delta. Certainly, for a value of a quantity of SSblocks, the offset delta is optional and may be or may not be a part ofthe time resource information. For example, in FIG. 7, n is 3. Forexample, with reference to FIG. 7 and the reference information, it mayindicate whether an SS block used for measurement window-basedcalculation is an SS block of the current cell or an SS block of theneighboring cell.

For all the forms of the time resource information, optionally, thereference signal notification message may include the referenceinformation. In implementation, the reference information may beseparated from the reference signal notification message. For example,the reference information is carried in another message (which is, forexample, named a first message) sent by the network device, for example,a broadcast message or a system message.

Optionally, the reference information may be classified into thereference information in which the current cell is used as a referenceor the reference information in which the neighboring cell is used as areference. Optionally, if a network system is a synchronous network, atime difference (English: time difference) between network devices maybe less than a length of a CP, and therefore the reference informationmay indicate that the time resource information is based on the currentcell. Optionally, if a network system is an asynchronous network, a timedifference between network devices may be greater than a length of a CP,and therefore the reference information may indicate that the timeresource information is based on the neighboring cell. Certainly, if thenetwork system is an asynchronous network, the reference information mayalternatively indicate that the time resource information is based onthe current cell. In this case, the reference signal notificationmessage or the another message (which is, for example, named the firstmessage) sent by the network device, for example, the broadcast messageor the system message, may further include a time difference between thecurrent cell and the neighboring cell, so that after receiving the timedifference between the neighboring cell and the current cell, the UEobtains a time location of the reference signal based on the timeresource information and the reference information, to receive thereference signal.

Supplementary description of the embodiment of the apparatus 1100 is asfollows:

The reference signal notification message further includes referenceinformation used to indicate whether the time resource information isbased on the current cell or the neighboring cell.

Optionally, the transceiver is further configured to send a firstmessage. The first message may be a broadcast message. The firstmessage, for example, the broadcast message, includes the referenceinformation used to indicate whether the time resource information isbased on the current cell or the neighboring cell.

For description of the reference information, refer to the descriptionin the foregoing embodiments. Details are not described again.

Supplementary description of the embodiment of the apparatus 1200 is asfollows:

The reference signal notification message further includes referenceinformation used to indicate whether the time resource information isbased on the current cell or the neighboring cell.

Optionally, the transceiver is further configured to receive a firstmessage. The first message may be a broadcast message. The firstmessage, for example, the broadcast message, includes the referenceinformation used to indicate whether the time resource information isbased on the current cell or the neighboring cell.

For description of the reference information, refer to the descriptionin the foregoing embodiments. Details are not described again.

All or some of the foregoing embodiments may be implemented by usingsoftware, hardware, firmware, or any combination thereof. When softwareis used to implement the embodiments, all or some of the embodiments maybe implemented in a form of a computer program product. The computerprogram product includes one or more computer instructions. When thecomputer program instructions are loaded and executed on a computer, allor some of the procedures or functions according to the embodiments ofthe present invention are generated. The computer may be a generalpurpose computer, a dedicated computer, a computer network, or anotherprogrammable apparatus. The computer instructions may be stored in acomputer readable storage medium or may be transmitted from a computerreadable storage medium to another computer readable storage medium. Forexample, the computer instructions may be transmitted from a website,computer, server, or data center to another website, computer, server,or data center in a wired (for example, a coaxial cable, an opticalfiber, or a digital subscriber line (DSL)) or wireless (for example,infrared, radio, or microwave) manner. The computer readable storagemedium may be any usable medium accessible by a computer, or a datastorage device, such as a server or a data center, integrating one ormore usable media. The usable medium may be a magnetic medium (forexample, a floppy disk, a hard disk, or a magnetic tape), an opticalmedium (for example, a DVD), a semiconductor medium (for example, asolid state disk (Solid State Disk, SSD)), or the like.

It should be understood that the term “and/or” in the embodiments of thepresent invention describes only an association relationship fordescribing associated objects and represents that three relationshipsmay exist. For example, A and/or B may represent the following threecases: Only A exists, both A and B exist, and only B exists. Inaddition, the character “/” in this specification generally indicates an“or” relationship between the associated objects.

A person of ordinary skill in the art may be aware that in combinationwith the examples described in the embodiments disclosed in thisspecification, units and algorithm steps may be implemented byelectronic hardware or a combination of computer software and electronichardware. Whether the functions are performed by hardware or softwaredepends on particular applications and design constraints of thetechnical solutions. A person skilled in the art may use differentmethods to implement the described functions for each particularapplication, but it should not be considered that the implementationgoes beyond the scope of the present invention.

It may be clearly understood by a person skilled in the art that for thepurpose of convenient and brief description, for a detailed workingprocess of the foregoing system, apparatus, and unit, refer to acorresponding process in the foregoing method embodiments. Details arenot described herein again.

In the several embodiments provided in this application, it should beunderstood that the disclosed system, apparatus, and method may beimplemented in other manners. For example, the described apparatusembodiment is merely an example. For example, the unit division ismerely logical function division and may be other division in actualimplementation. For example, a plurality of units or components may becombined or integrated into another system, or some features may beignored or not performed. In addition, the displayed or discussed mutualcouplings or direct couplings or communication connections may beimplemented by using some interfaces. The indirect couplings orcommunication connections between the apparatuses or units may beimplemented in an electrical form, a mechanical form, or another form.

The units described as separate parts may or may not be physicallyseparate, and parts displayed as units may or may not be physical units,may be located in one position, or may be distributed on a plurality ofnetwork units. Some or all of the units may be selected based on actualrequirements to achieve the objectives of the solutions of theembodiments.

In addition, function units in the embodiments of the present inventionmay be integrated into one processing unit, or each of the units mayexist alone physically, or two or more units are integrated into oneunit.

When the functions are implemented in a form of a software function unitand sold or used as an independent product, the functions may be storedin a computer readable storage medium. Based on such an understanding,the technical solutions of the present invention essentially, or thepart contributing to the prior art, or some of the technical solutionsmay be implemented in a form of a software product. The computersoftware product is stored in a storage medium, and includes severalinstructions for instructing a computer device (which may be a personalcomputer, a server, a network device, or the like) to perform all orsome of the steps of the methods described in the embodiments of thepresent invention. The foregoing storage medium includes any medium thatcan store program code, such as a USB flash drive, a removable harddisk, a read-only memory (Read-Only Memory, ROM), a random access memory(Random Access Memory, RAM), a magnetic disk, or an optical disc.

The foregoing descriptions are merely specific implementations of thepresent invention, but are not intended to limit the protection scope ofthe present invention. Any variation or replacement readily figured outby a person skilled in the art within the technical scope disclosed inthe present invention shall fall within the protection scope of thepresent invention. Therefore, the protection scope of the presentinvention shall be subject to the protection scope of the claims.

What is claimed is:
 1. A reference signal notification method,comprising: sending, by a network device, a reference signalnotification message, wherein the reference signal notification messagecomprises time resource information of a reference signal.
 2. The methodaccording to claim 1, wherein the reference signal is a CSI-RS, and thetime resource information is at least one of subframe configurationinformation, a time offset, or measurement window information of theCSI-RS.
 3. The method according to claim 1, wherein the reference signalis the CSI-RS, and the reference signal notification message furthercomprises one or more pieces of the following information: beaminformation of the CSI-RS, a cell identity, period informationcorresponding to a subframe of the CSI-RS, bandwidth information of theCSI-RS, antenna port information of the CSI-RS, numerology informationof the CSI-RS, or time-frequency resource mapping relationshipinformation of the CSI-RS.
 4. The method according to claim 1,comprising: sending, by the network device, the reference signalnotification message to the terminal device UE, wherein the networkdevice is a network device in a current cell of the UE, or the networkdevice is a network device in a neighboring cell of a current cell ofthe UE.
 5. A reference signal notification method, comprising:receiving, by a terminal device, a reference signal notificationmessage, wherein the reference signal notification message comprisestime resource information of a reference signal.
 6. The method accordingto claim 5, comprising: receiving, by the terminal device, a referencesignal notification message sent by a network device in a current cell,or receiving, by the terminal device, a reference signal notificationmessage sent by a network device in a neighboring cell of a currentcell.
 7. A reference signal notification apparatus, comprising atransceiver, wherein the transceiver is configured to send a referencesignal notification message, wherein the reference signal notificationmessage comprises time resource information of a reference signal. 8.The apparatus according to claim 7, wherein the reference signal is aCSI-RS, and the time resource information is at least one of subframeconfiguration information, a time offset, or measurement windowinformation of the CSI-RS.
 9. The apparatus according to claim 7,wherein the reference signal is the CSI-RS, and the reference signalnotification message further comprises one or more pieces of thefollowing information: beam information of the CSI-RS, a cell identity,period information corresponding to a subframe of the CSI-RS, bandwidthinformation of the CSI-RS, antenna port information of the CSI-RS,numerology information of the CSI-RS, or time-frequency resource mappingrelationship information of the CSI-RS.
 10. The apparatus according toclaim 7, wherein the time resource information and/or the beaminformation are/is information about one or more SS blocks fed back by aterminal device.
 11. The apparatus according to claim 7, wherein thetransceiver is further configured to send the reference signalnotification message to the terminal device UE, wherein the referencesignal notification apparatus is a network device in a current cell ofthe UE, or the network device is a network device in a neighboring cellof a current cell of the UE.
 12. A reference signal notificationapparatus, comprising a transceiver, wherein the transceiver isconfigured to receive a reference signal notification message, whereinthe reference signal notification message comprises time resourceinformation of a reference signal.
 13. The apparatus according to claim12, wherein the reference signal is a CSI-RS, and the time resourceinformation is at least one of subframe configuration information, atime offset, or measurement window information of the CSI-RS.
 14. Theapparatus according to claim 12, wherein the reference signal is theCSI-RS, and the reference signal notification message further comprisesone or more pieces of the following information: beam information of theCSI-RS, a cell identity, period information corresponding to a subframeof the CSI-RS, bandwidth information of the CSI-RS, antenna portinformation of the CSI-RS, numerology information of the CSI-RS, ortime-frequency resource mapping relationship information of the CSI-RS.15. The apparatus according to claim 12, wherein the time resourceinformation and/or the beam information are/is information about one ormore SS blocks fed back by a terminal device.
 16. The apparatusaccording to claim 12, wherein the transceiver is configured to receivea reference signal notification message sent by a network device in acurrent cell, or the transceiver is configured to receive a referencesignal notification message sent by a network device in a neighboringcell of a current cell.
 17. The apparatus according to claim 7, whereinthe reference signal notification message further comprises referenceinformation used to indicate whether the time resource information isbased on the current cell or the neighboring cell.
 18. The apparatusaccording to claim 7, wherein the transceiver is further configured tosend a broadcast message, wherein the broadcast message comprisesreference information used to indicate whether the time resourceinformation is based on the current cell or the neighboring cell. 19.The apparatus according to claim 12, wherein the reference signalnotification message further comprises reference information used toindicate whether the time resource information is based on the currentcell or the neighboring cell.
 20. The apparatus according to claim 12,wherein the transceiver is further configured to receive a broadcastmessage, wherein the broadcast message comprises reference informationused to indicate whether the time resource information is based on thecurrent cell or the neighboring cell.